Alzheimer's Disease is a major neurological disorder of the elderly affecting as much as 50% of the population over 80. No cure for this disease is known and its etiology is obscure. A major focus of this project is to discover the role of Amyloid Precursor Protein in neuronal cell death associated with Alzheimer's Disease. Over-expression of mutated forms of this protein (associated with early onset Familial Alzheimer's Disease) in neuronal cells leads to apoptosis. Anti-oxidants prevent this death and an increase in the accumulation of reactive oxygen species in these cells suggests increased oxidative stress as a mechanism of this cell death. Endothelial cells over-expressing mutant proteins show reduced adhesiveness and reduced formation of capillary networks suggesting a functional deficit in cells lining brain capillaries in Alzheimer's Disease.